Automatic warehousing facilities are well known which are of the type having a plurality of three-dimensional racks arranged in parallel, a travel path provided between each two adjacent racks and extending along the racks, a traveling crane movably mounted on each travel path to carry out goods take-in and take-out operations, and a station located at one end of each travel path for handling incoming and outgoing goods. In such an automatic warehousing facility, it is required that for maintenance and inspection purposes, or in case of emergency, an operator must enter the travel path of the crane. This poses a serious safety problem. There may be a danger of injury or death if the operator should carelessly step into the travel path when the crane is in automatic operation, or if the crane should start moving on account of misoperation or otherwise when the operator is present in the travel path.